Such an air-cleaning cartridge has become known from DE-B 10,96,759. This reference discloses a cylindrical outer wall, which consists of an elastically yielding material, e.g., rubber, provided between the two respiration connections in the prior-art air-cleaning cartridge. The cartridge is filled, while the container is open to the atmosphere, with a granular chemical, which absorbs, e.g., the CO.sub.2 present in the exhaled air in a gas mask and breathing equipment in order to again feed the respiration air thus treated to the user of the apparatus. The elastic wall part of the air-cleaning cartridge is expanded by the weight of the packing as the degree of filling progresses, so that the granular packing is subject to the contracting force of the expanded wall part when the cartridge is completely filled. The particles of the packing are held together by this contracting force and packed in a firm unit. The purpose of such a cartridge is to compensate for the reduction of the volume of the packing as a consequence of the expected contracting force during use, so that the flow of the respiration air through the cartridge will take place along the granules of the packing in order to achieve as complete treatment of the respiration air as possible. Otherwise, so-called bypass channels would be formed which would be passed through by the respiration air without flowing past the granules of the packing.
However, it proved to be disadvantageous that the expandability of the elastic housing wall under the intrinsic pressure of the packing is insufficient to keep the packing, whose weight may reach several kg, under a compressing force even during prolonged storage time to the extent that the granules of the packing will remain closely packed, even during a possible transport. When selecting the materials suitable for this purpose, one was limited to materials which were able to accommodate the heavy packing, but consequently did not have sufficient expandability to exert a sufficient contracting pressure, or to materials that were expandable to the extent that an initial contracting pressure was perhaps able to be applied to the granules of the packing after completion of the filling, but whose elasticity decreased during prolonged storage to the extent that even the contracting force dropped to a negligibly low value. In particular, the prior-art expandable air-cleaning cartridge for the above-mentioned reasons is less suitable for receiving especially large packings, which are required in connection with the considerable prolongation of the time of use of the gas masks and breathing equipment in which these air-cleaning cartridges are used. Depending on the variations in the weight of the packing, the prior-art air-cleaning cartridge expands more or less, as a result of which the contracting force thus generated will also assume different values. If one wished to further increase the contracting force in the prior-art filled air-cleaning cartridge it would be necessary to apply a mechanical pressure to the complete packing in order to further expand the wall of the cartridge. However, the application of such a mechanical force would lead to breakage of the granules of the packing, and, as a result, the packing density needed for operation would change. Dust, which settles in the spaces between the granules and increases the flow resistance, is formed due to the fracture on the granules of the chemical.